biopsychology

What is a dendrite?

-contain receptors which receive signals
-carry information down to cell body

what is a cell body/soma?

includes a nucleus

what is an axon?

-carries a signal/impulse down the length of the neuron
-covered in myelin sheath

what is a terminal button?

-communicates with the next neuron
-sends the signal to another neuron/muscle organ

What is the nucleus?

-contains genetic material/DNA

What are the nodes of Ranvier?

-force the signal to jump down the axon

What is the myelin sheath?

-the skin that protects the axon

What is a motor neuron?

-rcieves signals from the brain
-send it to muscles/organs/glands
-down from brain

what is a relay neuron?

-connects the motor/sensory neuron together
-only in CNS and eyes
-to and from brain

What is a sensory neuron?

-receives information from the environment and sends the signal to the brain
-to the brain

What is a synapse?

when the dendrites of one neuron connect to the terminals of the previous neuron. interlock like lock and key but they never touch, creating a gap

what is the process of synaptic transmission?

1\.Pre-synaptic transmission

2.The vesicles

3\.Post synaptic transmission

Pre-synaptic transmission

In the pre synaptic terminal, vesicles containing neurotransmittors are carried towards the axon terminal and are released into the synapse.electrical signal

The vesicles in synaptic transmission

the vesicles are diffused into the synaptic gap and neurotransmitters are released into the synapse.signal converted into a chemical impulse

Post synaptic transmission

the dendrites containing receptors,receive the signal.converted back into an electrical impulse,vesicles reform and the process restarts

what direction does information travel in a synapse?

one direction-contains receptors so they cannot send a signal and can only receive them

What is an excitation synapse?

neurotransmitter increases the positive charge of the postsynaptic neuron

increasing likelihood that the neuron will fire and pass on the electric response e.g.sugar/caffeine/adrenaline

What is an inhibition synapse?

neurotransmitter increases the negative charge of the post synaptic neuron

decreasing the likelihood that the neuron will fire an electrical response e.g.alcohol/sleeping pills

When a neuron is in resting state the inside of a cell is....

negatively charged compared to the outside

when a neuron is activated by a stimulus, the inside of a cell becomes...

positively charged for a split second causing an action potential to occur. This causes an electrical impulse down the axon towards the pre-synaptic transmission

Endocrine system

-governs release of hormones within the body into the bloodstream

pituitary gland

-master gland
-controls release of hormones from all the other endocrine glands in the body
-oxytocin released-used for reproductive behavior-released following orgasm by eliciting feeling of relaxation and calm
-kosfelt et al (2005)-high levels of oxytocin encourage strong bonding between couples

ovaries

-release oestrogen
-affect female behaviours-nurturing,caring
-transexuals given oestrogen treatment so behaviour correlates with female traits

Adrenal gland

releases adrenaline from the adrenal medulla

fight or flight response

The hypothalamus recognises a threat, the pituitary gland sends a message to the adrenal medulla triggering the release of adrenaline to the endocrine system and noradrenaline in the brain prompting physical changes

eye sympathetic and parasympathetic response

dilate pupils to improve peripheral vision
constrict pupils

heart sympathetic and parasympathetic response

speed up heart rate to speed up blood flow to vital organs and improve spread of adrenaline
slow down heart rate

gut/stomach sympathetic and parasympathetic response

inhibits digestion to save energy for prioritised functions like running
stimulates digestion

role of adrenaline
if faced with a \_______ situation, the \_______ branch of the nervous system functions for \________ action. This is known as the \_____ \__ \____ system. It is an \________ advantage to increase \_______. However it is regarded as being less advantageous today, e.g. not useful for \____ situations or \____tests. When a threat is \_____, the \______ medulla releases \______ into the \______. The \_______ branch stimulates the fight or flight response to threatening situations, and the \_______ branch returns the body to its normal state

threatening,sympathetic,immediate,fight or flight,evolutionary,survival,exam,driving,percieved,adrenal,adrenaline,bloodstream,sympathetic,parasympathetic

The peripheral(outer) nervous system consists of....

autonomic NS and Somatic NS

autonomic nervous system

-controls centers in brain stem
-governs the smooth muscle of the internal organs and controls involuntary functions of the body
-completely self regulating-functions unconsciously
purely motor pathways

somatic nervous system

-transmits information from our 5 senses through receptors to the CNS
-carries commands from motor cortex
-recieves info from the CNS, controls skeletal muscles,movement etc.
-sensory and motor neurones
-concious sytem

sympathetic nervous system

increases a bodys response (fight or flight)

parasympathetic nervous system

slows down a bodys response (rest and digest)

what are the two parts of the CNS?

brain and spinal cord

brain

contains
-brain stem-sleeping/walking/breathing
-cerebellum-balance and coordination
-cerebral hemisphere-higher thought function

spinal cord

receives messages TO and FROM the brain and connects to nerves in the PNS

Localisation of function

when a function is dealt with by 1 of the 4 lobes-known as localised

hemispheric lateralisation

if a function is dealt with by one hemisphere it is said to be lateralised-brain split into 2 hemispheres and each hemisphere is responsible for separate functions

Localisation theory

if an area of the brain becomes damaged, then the deficit will be permanent so the recovery of that function wouldn't be possible

Holistic Theory

brain is multi functional so if an area of the brain becomes damaged it is possible that the function of the brain will be transferred onto a healthy undamaged part of the brain through a process called plasticity

Phineas Gage

-suffered a severe brain injury from an iron rod penetrating his skull, of which he miraculously survived.
-After the accident, Gage's personality was said to have changed as a result of the damage the frontal lobe of his brain.
-The frontal lobes are the seat of the neural networks that determine our personalities.
-famous in the field as it shows the resilience of the human brain and illustrates how certain areas of the brain have different functions and contribute to our personality.

Phineas Gage GRAVE

G-cannot be generalised
R-impossible to replicate
A-led to new research and theories
V-acquired though friends and family. no cause and effect
E-no confidentiality or protection

contralateral function

each side of the brain controls the opposite side of the body

Frontal Lobe

-known as the motor area
-sends messages via the brain stem and spinal cord
-damage may make you paralysed (left frontal lobe damage\=paralysis on right side)
-important for complex voluntary movement

Broca area

-located in left frontal lobe
-responsible for speech production
-damage would result in brocas aphasia-speech lacks fluency
-speech would be lower/less comprehensive

parietal lobe

-aka somatosensory area
-refers to senation of body
-processes sensory information

Temporal lobe

-aka auditory lobe
-deals with sound and understanding language
-if primary auditory cortex is damaged-not total deafness as sounds can still be heard but require complex processing

Wernicke's area

-located in left temporal lobe
-responsible for speech recognition
-damage would result in struggle to find word needed and pronounce nonsense words

occipital lobe

-aka visual area
-processes visual information
-damage results in blind sight-see things consciously but unconsciously can still see as the eyes are still working

corpus collosum

bridge between two hemispheres-bundle of fibres which is effectively a communication pathway so that two hemispheres can exchange info

left hemisphere controls...

right side of body, language,reasoning

right hemisphere controls...

left side of the body,spatial awareness,facial recognition,drawing tasks

Sperry - Split Brain Research

Aim: To examine the extent to which the two hemispheres are specialised for certain functions.
Method: Image/word is projected to the patient's left visual field (which is processed by the right hemisphere) or the right visual field (which is processed by the left hemisphere). When information is presented to one hemisphere in a split-brain patient, the information is not transferred to the other hemisphere (as the corpus callosum is cut).
Conclusion: The findings of Sperry and Gazzaniga's research highlights a number of key differences between the two hemispheres. Firstly, the left hemisphere is dominant in terms of speech and language. Secondly, the right hemisphere is dominant in terms of visual-motor tasks.

Evaluation of sperry research

-Split-brain supports lateralised functions - useful in understanding the role of each hemisphere and the extent to which they are lateralised; left - language and speech; right - visual motor tasks.
-Small sample - argued the findings cannot be widely accepted, as split-brain patients are such an unusual sample of people. Only 11 patients took part in all variations and all had a history of seizures. may have caused unique changes in the brain that influenced the findings. limits the extent to which the findings can be generalised to normal brains, reducing the validity
-Some patients had greater disconnection than others - some patients can develop complex behaviours eg Alien Hand Syndrome , where other patients seem to function quite normally following surgery. difficult to draw conclusions from the findings, affecting the validity

Leborgne

-french epileptic
-could only say "tan"
-post mortem performed after death and found a lesion in the left frontal lobe-broca linked this damage to the deficit leborgne suffered
-shows broca area is localised in the left frontal lobe and supports localisation of function in the brain

leborgne GRAVE

G-not generalisable,epileptic,contacted sepsis
R-cant be replicated
A-yes,shows us there are language centres in the brain
V-yes but originally an educated guess and hes dead
E-not ethical as brain is displayed with no concept/confidentiality

GR 2008

-following a series of headaches
-CT scan showed hemorrhage in left occipital lobe
-reported blind sight in her right visual field
- assessed after 3 weeks and after 12 months-still blind
-vision is localised in occipital lobe and supports LOF in brain

GR GRAVE

G-cant be generalised-30 v young
R-not replicable
A-tells us vision localised in occipital lobe
V-valid due to recent and good tech
E-respected her privacy,initials used

What is brain plasticity?

the brains ability to modify its own structure and function following changes within the body/in the external environment

what are the 2 ways in which plasticity can occur?

1.when we're learning and experiencing something new
2.as a result/injury/trauma due to illness/accident

Danelli (2003)

-2.5 yr old italian boy had surgery to remove brain tumour that covered most of left temporal lobe
-lost all language abilities but underwent years of intensive language rehabilitation
-by 17,recovered language ability
-supports functional recovery (neural reorganistation)

The rate of plasticity is greatest in \_______. Babies brains are \______-forever \_____ and developing.

childhood,plastic,learning

more stimulation\=

greater brain plasticity

However without stimulation...

can lead to extreme brain damage

Functional recovery

-form of plasticity to transfer functions in a damaged area to a healthy area.
-Recover a brain function following an injury/trauma

4 anatomical ways body can replace axon function in he brain after trauma

1.increases brain stimulation
2.axon sprouting
3.denervation sensitivity
4. recruitment of homologous areas

recruitment of the homologous areas

The brain transfers the function to similiar areas on the opposite side of the brain e.g. if Brocas aphasia occured on left frontal lobe,right side would compensate

neural regeneration (axon sprouting)

growth of new neurons/connections to compensate for damaged areas.New nerve endings connect with other undamaged nerve cells to form neuronal pathways

Factors affecting extent of recovery from brain injury

Age-young more likely to recover,deterioration of brain in old age
Gender-women recover better than men as their function is not lateralised
Physical exhaustion-drugs/alcohol/fatigue
Perseverance-intensive rehabilitation,committed to recovery process

4 ways of studying the brain from least to most accurate

-post mortems
-EEGs
-ERP's
-fMRI

Post mortems AO1 AO2

-technique involving analysis of brain following death.
-brain examined after death to try and correlate structural abnormalities/behaviour they suffered when alive
-eg leborgne

Post Mortems AO3

-no cause and effect-purely subjective,observed damage may not be linked to deficits under review
-no discomfort experienced as they're not alive
-provide foundations for understanding the brain-broca and wernicke relied on pm.

EEG'S AO1

-electrodes placed on scalps and record the electrical activity of brain.
-measure the activity of the cells immediately under the electrode using more electrodes to give fuller picture
-used in epileptic patients and sleep studies
-brain is resting,no activity

ERP'S AO1

-electrodes placed on scalp-detect neuronal activity in response to a stimulus that has been introduced by a researcher e.g. photo/music
-same apparatus as EEG but only record when given a stimulus

ERPs vs self report AO2

-recorded responses to nude pictures of the opposite sex
-questionnaire-women reported less aroused,men admitted arousal
-ERP showed both aroused-suggests ERP measures brain activity more accurately than self report

EEGs and ERPs AO3

-High temporal resolution
-reasonably accurate
-locates the stimulated area but NOT the exact neurons involved

fMRI AO1

-use magnetic field and radio waves to monitor blood flow
-measures change in energy released Hb,reflecting activity of brain via 02 consumption to give moving picture of brain
-region of interest can be compared during specific activity
-most accurate

fMRI AO3

-non-invasive-doesnt rely on radiation and is safe
-expensive-require trained operators
-small sample sizes-limited availability

circadian rhythms last...

24 hours e.g. sleep/wake cycle

infradian rhythms last...

longer than 24 hours e.g. menstrual cycle/SAD

Ultradian rhythms last...

less than 24 hors e.g. sleep cycle

circadian rhythms are determined by

1.internal biological clocks (endogenous pacemakers)
2.external factors in the environment (exogenous zeitgebers)

Circadian Sleep-Wake Cycles

-feel drowsy at night and alert during day time-exogenous zeitgeber
-biological clock left to its own devices without external stimuli influence called free running
-basic rhythm goverend by SCN which recieves info about light and exogenous zeitgeber can reset SCN

Siffre's cave study (circadian rhythm)

-Siffre underground stay with no clocks or light, believed the date to be a month earlier than it was. suggests that his 24-hour sleep-wake cycle was increased by the lack of external cues, making him believe one day was longer than it was. This highlights the impact of external factors on bodily rhythms.

Evaluation of circadian rhythms

-small samples - research is based on small samples and participants may not represent the wider population, meaning generalisations are limited
- poor control - many studies involve depriving participants of natural light not artificial light
-research into S/W cycle has economic implications in terms of managing worker productivity.

Menstrual cycle Infradian Rhythms

-The human female menstrual cycle is about 28 days. -Rising levels of oestrogen cause the ovary to develop and release an egg (ovulation).
Progesterone helps womb lining to thicken, readying the body for pregnancy.
If no pregnancy - womb lining comes away and leaves the body (menstrual flow)

Stern & McClintock (1998)-infradian rhythms

29 women with irregular periods. Pheromones were taken at different stages of their cycle, via a cotton pad under their armpits. These pads were cleaned and rubbed on upper lips of other participants. 68% experienced changes to their cycle which brought them closer to their 'odour donor'.

SAD infradian rhythms

-depressive disorder with a seasonal pattern.
-symptoms are triggered during winter months when the number of daylight hours becomes shorter.
SAD is an infradian rhythm called a circannual rhythm (yearly cycle).

Infradian Rhythms AO3 SAD

photo therapy thought to reset melatonin levels recorded placebo affect using 'sham-negative-ion generator' may only be less effective due to higher expectations

Infradian Rhythms AO3 menstrual cycle

may have been advantageous for ancestors-collective offspring \=increased survival. Schank questions validity-cycling together produces competition for highest quality males-avoidance of synchrony would be most adaptive evolutionary strategy.Exogenous zeitgebers can influence cycle like pheromones

ultradian rhythms

could have more than one within a 24 hr period eg stages of sleep-90 mins

stages of sleep

1 and 2. Lightest Sleep (NREM)
3 and 4. Deeper Sleep (NREM)-Delta Waves omitted (NREM)
5. REM

Dement and Kleitman

sleep lab with 9 participants went through 5 stages of sleep used EEG and found if woken during REM dreams were remembered. showed that 1.5 distinctive stages to sleep 2.REM sleep is an important component of sleep cycle

Ultradian Rhythms AO3

EEGs contributed to understanding of sleep cycles and provide scientific value -have high temporal resolution and so detect sleep stages/brainwaves immediately

Endogenous pacemakers on the sleep wake cyle

SCN-primary ep-maintain circadian rhythms and recieve info about light

DeCoursey et al (2000)

influence of SCN on sw cycle by destroying 80 chipmunks connections in brain-in natural habitat for 80 days and lost sw cycle and killed by predators

endogenous mechanisms

pineal gland and melatonin

exogenous zeitgeber

light-direct influence on hormone secretion,blood circulation etc.can reset bodys main ez

exogenous and endogenous AO3

-research into SCN may obscure other body clocks as in many other cells/organs eg liver
-use of generalised findings from animals as cognitive factors may be more significant in humans.Ethics
-exo and endo interact so seperating for research presents unrealistic view of how systems work